Variation in selected hematological parameters of captive red-tailed hawks

Area of Science:

• Avian hematology
• Wildlife physiology
• Comparative physiology

Background:

• Understanding hematological parameters is crucial for assessing the health and physiological status of wild birds.
• Red-tailed hawks (Buteo jamaicensis) are apex predators whose physiological responses can indicate ecosystem health.
• Seasonal and diurnal variations in hematology can impact avian health and behavior.

Purpose of the Study:

• To investigate diurnal and seasonal variations in key hematological parameters in red-tailed hawks.
• To establish baseline hematological values for Buteo jamaicensis.
• To determine the significance of diurnal and winter changes in packed cell volume (PCV), erythrocyte count (RBC), plasma calcium, and plasma magnesium.

Main Methods:

• Blood samples were collected from 10 red-tailed hawks.
• Hematological parameters including PCV, RBC count, plasma calcium, and plasma magnesium were measured.
• Sampling occurred over a diurnal cycle and during the winter months (November-February).

Main Results:

• Significant diurnal variations were observed in packed cell volume (PCV) and erythrocyte (RBC) counts.
• No significant changes in any of the four parameters were detected when birds were sampled during winter.
• Individual variation among birds was significant for RBC count, PCV, and calcium concentration on a diurnal basis.

Conclusions:

• Diurnal fluctuations in PCV and RBC are notable in red-tailed hawks.
• Winter conditions did not induce significant changes in the measured hematological parameters.
• PCV exhibited significant diurnal variation and also varied significantly over the four-month winter period, suggesting its sensitivity to temporal factors.